It is a well-known fact that minerals have been widely used in the production of paper coatings, fillers and paints, just to mention a few. It is often the case that aqueous dispersions with a high content of solids are preferred, this brings with it high viscosity and consequently handling problems.
Dispersion of two of more components of distinct structure creates technical problems that must be resolved in order to manufacture the product containing the components, achieving the optimum packaging of said particles.
In order to improve viscosity and facilitate handling and processing, for example grinding, when working with a high content of solids, dispersants are usually added to the slurries. There are many dispersants that exist in the state of the art. They may be for example anionic polymers, such as neutralized polyacrylates of various salts. However, not all kinds of polyacrylates work ideally with distinct compositions. This proves there is a need to develop aqueous dispersions from minerals with a high content of solids using reduced amounts of polyacrylates.
Also, due to the role these products play, in most of their applications, it is important that they comply highly with respect to their capacity to cover, of whiteness and color (coloring capacity).
Another important aspect is the price of the components of the product. The characteristics of coverage, color and coloring capacity may be satisfactory using titanium dioxide, with very good results; however, the cost of this component increases the price of the product too much, thus making it necessary to find partial substitutes (extenders).
These are the gaps that organic and inorganic material mineral compositions present in the state of the art.
Existing calcium carbonates and kaolin, in any presentation, are basically pigment fillers or extenders which are used, for example, in the paint industry, basically to decrease costs, and do not provide the same physical characteristics and optical properties as pigments with structured minerals, such as: coverage, whiteness, gloss and coloring capacity.
With a view of achieving the characteristics indicated in the previous paragraph, exploration was begun into the size of existing carbonate and kaolin particles, making important progress as presented in U.S. Pat. No. 5,676,747, in which the granulometric structure of calcium carbonate which achieves the desired characteristics of coating ability is indicated.